CHARACTERIZATION OF AROMATIC STRUCTURES IN HUMIC AND FULVIC-ACIDS

The degradation technique, originally applied to the study of aromatic units in lignin, was used to characterize the aromatic structures pre sent in humic and fulvic acids. The method includes two oxidation step s, one with potassium permanganate and the other with hydrogen peroxid e. The phenolic hydroxyls are protected by ethylation before oxidation . Metylation of the formed acids enables gas chromatographic/mass spec trometric analysis. Humic acids gave more aromatic degradation units t han fulvic acids, but the same aromatic structures were observed in bo th humic and fulvic acids. More phenolic than nonphenolic units were f ound. The main phenolic degradation product was p-ethoxybenzoic acid, both in humic and fulvic acids. The results are also discussed in rela tion to the formation of the strong mutagen Z-2-chloro-3-dichloromethy l-4-oxobutenoic acid, MX, by aqueous chloronation of humic and fulvic acids.